International Business Machines Corporation

Storage Technology Corporation

Other

Richard C Schneider

James Mitchell Karp

Jack Chiu-Chiu Yuan

Vern Lee Watts

Steve T Kuo

Judy Y Tse

Stephen C West

Richard G Hannan

Mark Neal Ziebarth

Steven W Roach

Steven Michael Bock

Thomas Phillip Bridges

Jerome Joseph Zentner

Peter Anthony Franaszek

Martin Aureliano Hassner

Keith Gary Boyer

Gene H Sonu

Morovat B Tayefeh

Roy Lee Adler

Volker W Zimmermann

David C Graves

Khiet Quang Nguyen

Robert Shiwen Lai

Paul J Dounn

Terry L Kise

Roy F Dent, Iii

Norman Lee Koren

Communication between one system and another system using one communication mechanism has failed. The one communication mechanism includes an operating system service to transfer a message between the one system and the other system. Based on determining that the communication between the one system and the other system has failed, automatically switching from the one communication mechanism to another communication mechanism to communicate the message between the one system and the other system. The other communication mechanism is different from the operating system service and uses a coupling facility list structure.

Communicating between systems using a coupling facility list structure

According to one embodiment, a method for queuing a transaction request. The method may include receiving, by a processor, at least one transaction request from a transaction processing system. The method may also include storing the at least one received transaction request in a queue within a 64-bit storage system. The method may further include monitoring a 31-bit storage system. The method may also include determining at least one control block within the monitored 31-bit storage system is available. The method may further include transmitting the at least one stored transaction request to the monitored 31-bit storage system.

Using 64-bit storage to queue incoming transaction server requests

A system for satisfying a request from a client for a send-then-commit transaction includes a front-end information management system (IMS) server. Shared message queues (SMQ) communicate with the front-end IMS server and plural back-end IMS. The front-end IMS server receives the request from the client and transmits the request to the SMQ. A back-end IMS server accesses the SMQ and generates a transaction output in response to the request. The back-end IMS server transmits the result to the front-end IMS server and the front-end IMS server interfaces with the client to communicate the response thereto. The back-end IMS server and front-end IMS server operate in separate system images, but work together in a resource recovery services (RRS) environment to commit or backout the transaction output.

System and method for processing transactions in a multisystem database environment

Disclosed is a system, method, and program for accessing an application program, such as a transaction manager. A request for a file is received. The request includes a pathname and the pathname includes at least one directory name and the file name. The pathname is processed by a file system to determine whether the request is for a file on a storage device or an operation for the application program to perform. The file request is processed to generate a control message for the application program after determining that the request is not for a file on the storage device. The control message is then passed to the application program to cause the application program to perform an operation.

METHOD, SYSTEM FOR USING FILE NAME TO ACCESS APPLICATION PROGRAM WHERE A LOGICAL FILE SYSTEM PROCESSES PATHNAME TO DETERMINE WHETHER THE REQUEST IS A FILE ON STORAGE DEVICE OR OPERATION FOR APPLICATION PROGRAM

In an IMS/ESA environment, an ITASK is provided so as periodically to check IMS application programs to determine whether any is hung, thus providing notification for hung transactions that sometimes occur after an asynchronous APPC call issued by IMS from the IMS dependent region during syncpoint processing. APPC calls cause a time stamp to be written, which is used by the ITASK to determine how long the transaction is in a response wait state. The ITASK is reactivated after a waiting period dynamically determined on the basis of the processes active and a minimum interval. Detection of hung transactions results in a remedial action being taken.

Timeout detection facility

Dropout produces amplitude and high frequency loss in the read signal produced by reading a magnetic tape. A system for dropout compensation includes an adaptive filter that filters the read signal using multiplicative weighting factors based on an error signal. A detector receives the adaptive filter output and produces a binary signal indicating data written onto the magnetic tape. A shaping filter receives the binary signal and produces an ideal read signal representing the read signal resulting from writing and subsequently reading the binary signal without dropout. A differencer determines the error signal by subtracting the adaptive filter output from the ideal read signal.

Signal dropout compensation

A method of generating an encoded signal from a sequential stream of digital data, where the encoded signal has a non-power carrying null state and a power carrying active state with two opposing polarities. Logical one bits are distinguished from logical zero bits by inverting the encoded signal's polarity at the start of only the logical one bits. The encoded signal is set to the active state during a bit set-up period before, and held in the active state during a bit hold period after each polarity inversion. At other times the encoded signal is set to the null state. The method may include the addition of equalization pulses during strings of consecutive logical zero bits to keep the encoded signal from remaining in the null state for extended periods. Each equalization pulse may be preceded by an equalization set-up period and followed by an equalization hold period where the encoded signal is in the active state. In the preferred embodiment the set-up periods, hold periods, and equalization pulse periods are one-third the duration period of the logical bits.

Power-tailored write-current method

Method and apparatus for detecting valid data peaks read from a magnetic medium. Signals representing the peaks are entered into a shift register. Logic circuitry including comparator are connected to stages of the shift register to determine the relative magnitude of a peak sampled at time N versus subsequently sampled peaks. The generated magnitude information is used to determine which of the signals represent valid data peaks and which represent noise and the like.

Method and apparatus for detecting valid data peaks

A ladder safety attachment designed to secure a ladder at its top to a tree or pole to prevent rocking or sliding of the ladder out of the position to which the ladder was initially set. The safety attachment includes a platform with two sets of spikes. The spikes in the first set are fixed in position with respect to the platform and are designed to engage a tree or pole as soon as the combined safety attachment and ladder are placed against the pole or tree, holding the ladder in its initial position while an operator ascends the ladder to engage the second set of spikes. The spikes in the second set are adjustable and are designed to accommodate various diameter trees or poles. The safety attachment further includes a adjustable set of ladder attachment brackets which can be adjusted to accommodate ladders of various sizes.

Ladder safety attachment

In a recordable media drive, error processing is implemented in an adjustable read channel equalizer in which gain and bandwidth values can be selectively adjusted. In a write/verify procedure, the gain value is reduced, while the bandwidth is increased, thereby stressing the read channel during verification of written sectors in order to force the failure of marginal sectors. In an error recovery procedure, when a sector error is encountered, the gain value of the adjustable equalizer is initially increased and a sequence of read retries of the failed sector is initiated.

Adjustable read channel equalization for error processing in a

A data clock is synchronized to a modulation coded signal read from a moving storage medium by a phase error estimator circuit that samples the modulation coded signal two times on each side of a detected peak. A first detected data bit taken at a time N- 2 (two time periods prior to the detected peak) is used to predict the expected value of a first modulation coded signal sample taken at a time N- 1 (one time period prior to the detected peak). Similarly, a second detected data bit taken at a time N+ 2 is used to predict the expected value of a second modulation coded signal sample taken at a time N+ 1. Because the first and second detected data bits are able to predict the first and second samples, respectively, the phase error estimator circuit is able to accurately detect phase errors when sampling arbitrary data as would be presented by a (1,k) modulation coded signal. The expected values at times N- 1 and N+ 1 are compared to the actual values and error voltages are determined therefrom. The error voltages are multiplied by the appropriate slope factors, also determined by the first and second detected data bits, and error estimates E(N- 1) and E(N+ 1) are provided. E(N- 1) is added to E(N+ 1) to provide the phase error estimate E(N).

Digital phase error estimator

A record medium, such as a magnetic tape, optical disk, magnetic disk, and the like stores data signals and error redundancy signals. Resynchronization signals are interleaved between the recorded signals such that the error redundancy signals are usable to correct signals recorded between such interposed resynchronization signals wherein no error redundancy signals are recorded. Error pointing redundancy signals are recorded between all of the resynchronization signals for pointing to signals in error for enhancing the error correction. Such error pointing signals can be cyclic redundancy check (CRC) signals. Controls for taking advantage of the above-described arrangement are also described. Reframing and clock synchronization controls are also disclosed.

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Tucson, AZ, United States of America

Richard C Schneider